Chewing gums and bubble gums have been prepared in the past, with the purpose in mind of extending shelf life and providing improved chew texture. Characteristically, gums prepared and stored, even at room temperature for extended periods of time, tend to lose their moisture and elasticity, with the result that they become brittle, and initially crumble when they are placed in the mouth. This problem is particularly noticeable in the instance of sugarless gums, and particularly those gums that are stored in a dry atmosphere, i.e. an atmosphere having less than from 50 to 60% relative humidity.
Sugarless gums conventionally contain on the order of about 5% of water, and it is therefore theorized that brittleness or the phenomenon of staling results from the loss of that water, due to evaporation or otherwise, over time. Specifically, most sugarless gums contain large amounts of sorbitol, which serves conventionally as a sweetener, as well as a bulking aid. Sorbitol is known for its tendency to recrystallize in the presence of even small amounts of water, and its tendency to crystallize when the water in which it is dissolved is removed. It is therefore theorized that, as the water containing the sorbitol in the gum composition is lost by evaporation or otherwise, the sorbitol crystallizes and thus promotes the embrittlement of the gum composition, that contributes to the staling phenomenon. One workable approach to prolonging gum composition freshness relied on the use of fin-seal packaging with water vapor impermeable laminates to exclude all external ambient atmosphere and accompanying moisture and conversely to prevent the egress of moisture from the package contents. This approach is very costly and has its limitations, as periodic package leakage permits staling to occur unabetted as before.
Another approach has been to utilize anhydrous chewing gum compositions in conjunction with glycerin. For example, U.S. 4,514,422, issued to Yang et al on April 30, 1985, discloses a gum composition having improved shelf life and resistance to staling comprising a substantially anhydrous mixture of a gum base, at least one sugar alcohol, and glycerin. The glycerin is present in an amount from about 8% to about 18% by weight of the gum composition. The gum composition is further characterized by containing no more than 2% by weight of water in any form. The gum base may be present in an amount by weight ranging from about 15% to about 30% and the sugar alcohols may be present in an amount ranging from about 40% to about 75% by weight. The sugar alcohols utilized preferably comprise sorbitol, mannitol, xylitol and appropriate mixtures. Although Yang et al disclose that fatty acid monoglycerides may be used in their compositions, there is no disclosure or suggestion of the use of acetylated monoglycerides.
Pending U.S. application Ser. No. 846,690 filed April 1, 1986 of Cherukuri et al discloses a bubble gum base as well as a bubble gum composition which have excellent initial and extended chew properties, forms an essentially continuous film, maintains the bubble shape after the bubble has been formed and resists ingredient separation. These textural properties were produced from a unique combination of non-SBR elastomers, a combination of at least two different polyvinyl acetate polymeric materials and an acetylated monoglyceride which has a saponification value above about 400. The acetylated monoglycerides are used in amounts of about 5% to about 12% (by weight of the gum base composition). It is also disclosed that a variety of traditional ingredients, such as plasticizers or softeners, may optionally be added. Such materials are optional and not essential and amongst the exemplified materials there is included glycerine. Such materials are generally employed in amounts of about 6% to about 20% by weight of the gum base composition. It is disclosed that the gum base may be used in amounts of about 5% to about 45% of the final gum composition.
Cherukuri et al. U.S Pat. No. 4,352,822 on Oct. 5, 1982, reexamination certificate issued Sept. 3, 1985, discloses a non-styrene-butadiene rubber gum base comprising a polyisobutylene elastomer or a mixture of medium and lower molecular weight polyisobutylene elastomers together with a unique combination of plasticizers including glyceryl triacetate and acetylated monoglycerides together with a hydrophilic type detackifier, such as polyvinyl acetate and a combination of ingredients to impart non-stick properties. It is disclosed that the mixture of glyceryl triacetate and acetylated monoglyceride plasticizers are essential to the gum base for imparting softness and plasticization to the gum base. The glyceryl triacetate will be present in an amount of within the range of from about 0 to about 10%, and preferably from about 1 to about 8% by weight of the gum base, while the acetylated monoglyceride will be present in an amount of within the range of from about 0 to about 15%, and preferably from about 1 to about 10% by weight of the gum base. The gum base is employed with other chewing gum ingredients to form chewing gum compositions. The chewing gum compositions will include from about 10 to about 40% by weight of the gum base. Example 3 of the patent discloses a bubble gum using glycerine in the composition as a softener
Cherukuri et al. U.S. 4,352,823 issued on Oct. 5, 1982 discloses a coextruded chewing gum which is formed of an extruded soft non-styrenebutadiene gum center or core portion, and an outer gum or shell portion having a harder consistency than the soft gum center or core portion, coextruded with and about the soft core portion. In a preferred embodiment the core portion will contain in excess of 1%, usually above 5 and up to 10% moisture, and preferably from about 6 to about 8% by weight moisture, that is, amounts of moisture not normally employed in all-solid chewing gums. The core portion is soft, sticky and difficult to handle but through coextrusion techniques, the outer shell layer acts as a support and protective coating for the soft and sticky inner core portion.
The soft gum core portion of U.S. Pat. No. 4,352,823, will preferably be formed of a sugar containing chewing gum, although soft sugarless chewing gums may be employed as well In a preferred embodiment, the sugar containing soft gum core portion will have a short nougat-like or fondant-like structure, a long-lasting sweetness, a soft and smooth consistency, an amorphous bite through and easy chew and a high moisture content (from over about 5 to about 10%, preferably from about 6 to about 8% moisture).
The chewing gum forming the outer shell portion in U.S. Pat. No. 4,352,823 may comprise chewing gum formulations generally known in the art. Each of the core and shell chewing gums may be of the sugar-containing or sugarless variety. Thus, in the sugar-containing coextruded chewing gum of the invention, both the core and outer shell portions may be sugar-containing or one may be sugar-containing and the other sugarless.
The soft core portion in U.S. Pat. No. 4,352,823 gum base includes a combination of plasticizers including acetylated mono and triglycerides, and glyceryl triacetate together with a hydrophilic type detackifier and a combination of ingredients to impart non-stick properties. It is disclosed that the mixture of glyceryl triacetate and acetylated monoglyceride plasticizers are essential to the non-styrene-butadiene gum base for imparting softness and plasticization thereto. The glyceryl triacetate will be present in an amount within the range of from about 0 to about 10%, and preferably from about 1 to about 8% by weight of the gum base, while the acetylated monoglyceride will be present in an amount of within the range of from about 0 to about 15% and preferably from about 1 to about 10% by weight of the gum base.
U.S. Pat. No. 4,352,823 also discloses that the soft core portion will also include a premixed recrystallized combination of at least two sweeteners, including solid and liquid sweeteners, which preferably include sucrose and/or sorbitol and/or hydrogenated starch hydrolysate, and high fructose syrup alone or together with liquid glucose, hydrogenated starch hydrolysate syrup, corn syrup, sorbitol syrup and/or invert sugar, in the recrystallized mixture, and flavors, softeners and other conventional chewing gum ingredients.
According to U.S. Pat. No. 4,352,823 it is essential that the liquid and solid sweeteners mentioned above comprise a preformed combination of particulate solid sweetener particles which are coated with a syrup sweetener and which mixture has been heated, dried to a homogeneous mass, and then cooled to recrystallize the mass into an amorphous solid. The recrystallized sweeteners impart a soft smooth consistency and texture to the chewing gum, similar to that found in nougat-type or fondant-type candies and non-stick properties as well.
The above premixed combination of sweeteners may comprise a so-called "dry fondant" mix formed of the above-mentioned sweeteners which is reconstituted with water and then added to the gum base and other chewing gum ingredients to form the soft chewing gum core portion of the coextruded chewing gum.
A preferred soft gum core portion is disclosed in the paragraph bridging columns 8 and 9 in U.S. Pat. No. 4,352,823, which composition includes 0 to 2 parts by weight glycerin.
It is further disclosed that in another preferred embodiment, the core portion contains pure fructose syrup as a replacement for corn syrup.
U.S. Pat. No. 4,452,820 issued to D'Amelia et al. on June 5, 1984 discloses a single phase formulation for a homogeneous gum base composition containing an elastomer and a resin in the absence of ester gums required to compatibilize the elastomer. The composition comprises a plasticized styrene-butadiene elastomer and a plasticized resin. The exemplified plasticizers for the resin include glyceryl triacetate and acetylated monoglyceride among others. It is disclosed that combinations of plasticizers may be used with a preferred combination being glyceryl triacetate and acetylated monoglyceride.
Thus, a variety of formulations have been used to provide gum compositions with desired physical characteristics. However, there is still a need for gum compositions having a substantially uniform soft chew texture from the beginning of the chew to the final chew. It would be highly desirable to provide such a gum composition without the need to modify the gum base or produce a new gum base. It would also be highly desirable to have such a soft chew gum composition, particularly a sugarless gum composition, which utilizes lower limits of glycerin, which in turn results in a composition resistant to staling. This invention provides such compositions.